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Editor,—Primary epithelial amyloid keratopathy (PEAK) is a newly described entity of subepithelial amyloidosis. PEAK is an aggressive variant of primary gelatinous drop-like dystrophy in patients of eastern origin. We describe the clinical and histopathological findings of two brothers suffering from PEAK. The opacities recurred in one after epithelial scrapping and in the other after repeated penetrating keratoplasty.
Two patients of Iranian origin were treated in our department. Light microscopy, histochemistry, and electron microscopy were performed on epithelial scrapping, corneal buttons, and failed grafts.
Clinically, the two brothers presented with deterioration of vision, photophobia, and redness. Examination revealed corneal opacification of the central cornea, which also occurred in the grafts. Histopathological examination disclosed intraepithelial and stromal deposits of amyloid associated with inflammation.
The elder brother, now a 50 year old, has been suffering from visual disturbances and photophobia in both his eyes from the age of 14. During the past 20 years he had undergone five penetrating keratoplasties on his right eye and four on his left eye. The indication for surgery was repeated recurrence of the opacities in the graft (Fig 1). In four instances the opacities in his right cornea reappeared in the graft within 1 year after the corneal transplantation. Deposits of amyloid were found by histopathological examination.
The younger brother, now 41 years old, had been complaining of epiphora and deteriorating visual acuity from the age of 18. He underwent right eye corneal scraping and left eye penetrating keratoplasty at the age of 39. There was a short period of relative improvement in visual acuity after the epithelial scraping. However, subsequently, more opacities developed at the centre of the cornea and right eye penetrating keratoplasty was performed 2 years later.
Histopathological examination of the corneal buttons removed during perforating keratoplasties revealed corneal epithelium and stromal amyloid deposits (Fig 2), confirmed by Congo red stain and birefringence. Electron microscopy demonstrated non-branching fibrils of 7.5–10 nm inside the epithelial cells and around them in the area of the amyloid deposit. The deposits in the stroma were associated with an inflammatory infiltrate including granulomatous inflammation showing multinucleated, foreign body giant cells. Amyloid was also recovered from the scrapping material.
There was no known parental consanguinity. They remembered having a grandmother with very poor eyesight, yet they did not know the cause. None of the other six brothers or their children (all are very young) suffer from corneal disease.
These two brothers with PEAK, represent the relentless behaviour of this disease, with repeated recurrences, within a short period of time after scraping or penetrating keratoplasty.
Primary epithelial amyloid keratopathy (PEAK) is a variant of primary gelatinous corneal dystrophy, first described in 1994 by Edward and co-workers in patients who were of Asian-Indian or Iraqi origin1; another variant is primary drop-like corneal dystrophy which has been mainly described in Japan.2 3Patients with PEAK suffer from deterioration of vision, redness, and photophobia from childhood or adolescence whereas in primary gelatinous corneal dystrophy symptoms usually start at adulthood. On clinical examination there were corneal subepithelial nodules which tend to progress, associated with stromal opacification and neovascularisation. Histological examination of the corneas demonstrated multiple intraepithelial and subepithelial deposits at childhood while in adults the material was found also in the stroma.
Other patients suffering from PEAK1 3 were noted to be from India and Iraq, our patients originated from the same geographical area, Iran. It seems that this variant of gelatinous drop-like corneal dystrophy might be more prevalent in mid-Asian countries than was previously known. This variant differs from the one described in Japan in that it manifests at a younger age, is more aggressive and tends to reappear in corneal grafts.
To conclude, PEAK is an aggressive variant of primary gelatinous corneal dystrophy, demonstrating a devastating corneal disease starting at young age and no remedy even after corneal scraping or repeated penetrating keratoplasty.
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